Molding die for covering optical fiber and optical fiber cover forming device

ABSTRACT

An optical fiber coating mold which is comprised of upper and lower molds having joint surfaces, a molding portion where a coating formation portion of an optical fiber can be arranged and a supply passage for supplying UV curable resin being formed between the joint surfaces of the upper and lower molds when the joint surfaces are superimposed one upon the other, the molding portion being filled with UV curable resin after arranging the coating formation portion of the optical fiber in the molding portion, the coating formation portion of the optical fiber being coated with the UV curable resin when the UV curable resin is cured by irradiating light thereto from outside, in which a shading plate is arranged in the periphery of the molding portion. In a case equipped with such a mold, there is provided a mirror or a lens for reflecting UV light to UV curable resin, the mirror or the lens being provided so as to secure the field of view for observation of the interior through an observation window of the case.

TECHNICAL FIELD

[0001] The present invention relates to an optical fiber coating moldand an optical fiber coating forming device to be used to re-coat aportion of an optical fiber from which coating has been removed and tonewly coat the outer periphery of an optical fiber core.

BACKGROUND OF THE RELATED ART

[0002] When performing branching, distribution, etc. on optical fibers,the end portion of each optical fiber is exposed by removing the coatingby a predetermined length; after fusion—splice the end portions to eachother, the coating peeled-off portion (the portion requiring coatingforming: coating formation portion) is protected by reinforcing throughre-coating with UV curable resin. In some cases, the outer periphery ofthe optical fiber core is newly coated.

[0003] For re-coating, a coating forming device equipped with a mold isused. The mold is composed of a lower mold and an upper mold mountedthereto so as to be capable of being opened and closed. In the opposingsurfaces (joint surfaces) of the lower and upper molds, there are formedsemi-cylindrical re-coating grooves (molding grooves); when the uppermold is closed to be superimposed on the lower mold, their re-coatinggrooves are opposed to each other to define a cylindrical moldingportion. The coating formation portion of an optical fiber is placed inthis molding portion and then ultraviolet (UV) curable resin is suppliedto the interior of the molding portion; when UV light is irradiated tothe UV curable resin from outside the mold, the UV curable resin curesto re-coat the outer periphery of the coating formation portion.

[0004] From the viewpoint of convenience in accommodation, handling,etc., it is desirable that the coated portion be as small as possible.In view of this, nowadays, only the coating formation portion isre-coated with UV curable resin. Further, regarding re-coating, thereare the following requirements:

[0005] 1. With the development of Wavelength Division Mutiplexing (WDM)communication technology etc., there is a demand for production ofoptical fiber amplifiers and optical parts in a large amount, so that itis necessary to reduce the requisite processing time for the operations,such as optical fiber cutting, peeling-off of coating, connection ofoptical fibers, and coating of coating formation portions.

[0006] 2. Since more and more coating forming devices have come to beused where optical parts are produced, there is a demand for a reductionin size, weight, and power consumption for convenience in handling. Fora reduction in size and weight, the UV light utilization efficiencyshould be enhanced.

[0007] The above coating forming device makes it possible to coat thecoating formation portion of an optical fiber with resin. However, itinvolves the following problems:

[0008] (1) The UV light irradiated to the mold is irradiated not only tothe molding portion but also to its periphery. More specifically, the UVlight is also irradiated to the joint surfaces between the lower andupper molds, the supply passage for supplying UV curable resin to themolding portion, the supply port connecting the supply passage and themolding portion, etc. Thus, when the UV curable resin supplied into themolding portion is allowed to protrude over the joint surfaces, theresin will cure between the joint surfaces, resulting in difficulty inopening the upper mold or generation of burr in the coated portion.Further, when some UV curable resin remains in the supply passage andthe supply port, the resin will cure to clog the supply passage and thesupply port.

[0009] (2) In actual coating operation, there may be a case wheresufficient quantity of UV light does not reach the back side of thecoating formation portion of the optical fiber placed in the mold. Insuch a case, the UV light irradiation time is increased or UV curableresin with thermosetting property is used, heating the resin with aheater while irradiating UV light thereto. However, increasing the UVlight irradiation time makes it impossible to achieve a reduction in thetime consumed for the coating operation. Consequently, it involveslarger power consumption of the heater, according to the irradiationtime increase, resulting in high cost. Further, it causes difficulty inreducing the size of the UV lamp turning-on system, in particular, thehigh voltage power source.

[0010] (3) To enhance the UV light utilization efficiency, a coatingforming device has been developed in which a reflection plate equippedwith a concave reflection surface is arranged above the upper mold,wherein UV light is irradiated from below the lower mold, the UV lighttransmitted through the lower and upper molds being reflected by thereflection plate to be condensed on the UV curable resin in there-coating groove of the upper and lower molds. In this coating formingdevice, only a part of the UV light is transmitted through the lowermold to reach the upper mold, so that the quantity of reflection lightis rather small, which means a substantial improvement in terms of theUV light utilization efficiency can not be expected. Further, the uppersurface of the upper mold is covered by the reflection plate arrangedabove the upper mold, and the visual field for inspecting the interiorof the coating forming device is closed, making it impossible to checkthe way the optical fiber is placed in the coating forming device andthe way the mold is filled with UV curable resin. Further, since thereflection surface of the reflection plate is concave, it becomes largerin thickness than a reflection plate with a flat reflection surface,resulting in an increase in the size of the reflection plate, whichcauses difficulty in reducing the size of the coating forming device.

DISCLOSURE OF THE INVENTION

[0011] An optical fiber coating mold according to the present inventionis comprised of upper and lower molds having joint surfaces, moldinggrooves being formed in the joint surfaces of the upper and lower molds,a molding portion where a coating formation portion of an optical fibercan be arranged and a supply passage for supplying UV curable resinbeing formed between the opposing molding grooves of the upper and lowermolds when the joint surfaces of the upper and lower molds aresuperimposed one upon the other, the molding portion being filled withUV curable resin through the supply passage after arranging the coatingformation portion of the optical fiber in the molding portion, thecoating formation portion of the optical fiber being coated with the UVcurable resin when the UV curable resin is cured by applying lightthereto from outside, wherein a shading plate is arranged in theperiphery of the molding portion. According to an optical fiber coatingmold of the present invention, in the optical fiber coating mold, ashading plate for preventing light irradiated from outside from enteringthe supply passage may be arranged on the outer side of the supplypassage.

[0012] In an optical fiber coating forming device according to thepresent invention, a coating formation portion of an optical fiber isset in a molding portion of a mold set in a case, the outer periphery ofthe coating formation portion of the optical fiber in the moldingportion being filled with UV curable resin, the outer periphery of thecoating formation portion of the optical fiber being coated with the UVcurable resin when the resin is cured by irradiating UV light thereto,the mold consists of a mold described in claim 1 or 2, and the casingcontains a container for containing UV curable resin, a supplying devicefor supplying the UV curable resin in the container to the interior ofthe molding portion of the mold, a light source for generating UV lightto be irradiated to the mold, and a control unit for controlling thesupplying device and the light source.

[0013] In the optical fiber coating forming device of the presentinvention, a mirror or a lens for reflecting UV light to UV curableresin is provided in a casing, and the mirror or the lens is provided soas to secure the requisite visual field for an observation window forobserving the interior of the casing. Further, it is also possible toprovide a flat reflection plate behind the mold, to arrange a mirror ora lens on the back or side surface of the light source, or to make bothor one of the mirror and the lens movable. Further, it is also possibleto provide a shading plate for preventing UV light from being irradiatedto the UV curable resin in the portions other than the molding portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a perspective view showing a mold according to anembodiment mode of the present invention.

[0015]FIG. 2A is a perspective view showing a state in which the upperand lower molds shown in FIG. 1 are joined together.

[0016]FIG. 2B is a longitudinal sectional view showing a state in whichthe upper and lower molds shown in FIG. 1 are joined together.

[0017]FIG. 2C is a cross-sectional view showing a state in which theupper and lower molds shown in FIG. 1 are joined together.

[0018]FIG. 3 is a perspective view of an optical fiber coating formingdevice according to an embodiment mode of the present invention.

[0019]FIG. 4 is a back side view of the optical fiber coating formingdevice shown in FIG. 3 with its cover closed.

[0020]FIG. 5 is an explanatory drawing showing a control system of theoptical fiber coating forming device shown in FIG. 3.

[0021]FIG. 6 is a perspective view of an optical fiber coating formingdevice according to an embodiment mode of the present invention.

[0022]FIG. 7 is a perspective view showing an optical fiber coatingforming device according to the present invention with its cover closed.

[0023]FIG. 8A is a schematic diagram showing an example of the mold ofan optical fiber coating forming device according to the presentinvention.

[0024]FIG. 8B is a front view of the mold of FIG. 8A.

[0025]FIG. 8C is a side view of the mold of FIG. 8A.

[0026]FIG. 9 is a side view, partly in longitudinal section, showing anexample of the arrangement of the mold, mirror, and reflection plate inan optical fiber coating forming device according to the presentinvention.

[0027]FIG. 10 is an explanatory drawing showing how UV light isirradiated in the optical fiber coating forming device of FIG. 9.

[0028]FIG. 11 is a diagram illustrating a control system in an opticalfiber coating forming device according to the present invention.

[0029]FIG. 12 is a side view, partly in longitudinal section, showinganother example of the arrangement of the mold, mirror, and reflectionplate in an optical fiber coating forming device according to thepresent invention.

[0030]FIG. 13 is an explanatory drawing showing how UV light isirradiated in the optical fiber coating forming device of FIG. 12.

BEST MODE FOR CARRYING OUT THE INVENTION

[0031] (Embodiment Mode 1)

[0032] A mold of the present invention is used to cover a coatingformation portion of an optical fiber with UV curable resin. Anembodiment mode thereof will now be described.

[0033] As shown in FIG. 1, the mold of the present invention is composedof an upper mold 1 and a lower mold 2 which are connected so as to allowopening and closing. There is no particular restriction regarding thematerial of the upper and lower molds 1 and 2 as long as it transmits UVlight. Examples of the material include transparent quartz glass andplastic.

[0034] In joint surfaces 3 and 4 of the upper and lower molds 1 and 2,there are formed semi-cylindrical molding grooves 5 and 6 extending fulllength in the longitudinal direction. The molding grooves 5 and 6 areformed as semi-cylinders whose diameters are slightly larger than theouter diameter of the coating formation portion of the optical fiber.When, as shown in FIG. 2A, the upper mold 1 is put on the lower mold 2to superimpose their joint surfaces 3 and 4 one upon the other, the twomolding grooves 5 and 6 are opposed to each other to define acylindrical molding portion 7 as shown in FIGS. 2A through 2C, and aretaining portion 8 is formed on either outer side so as to extendcontinuously in the longitudinal direction. The molding portion 7accommodates the coating formation portion of the optical fiber, and theretaining portions 8 accommodate the coated portions of the opticalfiber on the both outer sides of the coating formation portion. Theinner diameter of the molding portion 7 is somewhat larger than theouter diameter of the coating formation portion of the optical fiberarranged therein. High precision mirror finishing is performed on thejoint surfaces 3 and 4 of the upper and lower molds 1 and 2 to restraingeneration of surface irregularities, thus enabling the joint surfacesto be brought into close contact with each other.

[0035] As shown in FIG. 1, in the joint surfaces 3 and 4 of the upperand lower molds 1 and 2, there are formed lateral grooves 10 and 11perpendicular to the molding grooves 5 and 6. As shown in FIGS. 2B and2C, the lower mold 2 has a vertical hole 13 one end of whichcommunicates with the lateral groove 11 and the other end of which leadsto the exterior. Due to the formation of the lateral groove 11 and thevertical hole 13, when the joint surfaces 3 and 4 of the upper and lowermolds 1 and 2 are superimposed one upon the other as shown in FIG. 2A,the lateral grooves 10 and 11 of the molds 1 and 2 are opposed to eachother to define a supply passage 15 as shown in 2C; when UV curableresin is supplied to the supply passage 15 from outside, the UV curableresin is supplied into the molding portion 7.

[0036] As shown in FIGS. 2A through 2C, a shading plate 20 is embeddedin the lower mold 2 so that UV light irradiated to the mold from belowthe lower mold 2 can be intercepted. The shading plate 20 is composed ofthin and narrow shading plates 20 a and 20 b embedded so as to extend inthe longitudinal direction of the molding groove 6 on either side of thecentral portion with respect to the longitudinal direction of themolding groove 6 (the portion that is at least opposed to the moldinggroove 5 of the upper mold 1 to define the molding portion 7), andshading plates 20 c and 20 d arranged at the bottom of the lateralgroove 11 and on a side of the vertical hole 13 so that no UV light mayenter the lateral groove 11 and the vertical hole 13. The shading plates20 b, 20 c, and 20 d are formed into a T-shaped integral unit. Theshading plates 20 a through 20 d are appropriately formed of a materialwhich reflects or absorbs UV light or prepared by forming an UVreflection film (e.g., dielectric multi-layer film) on a surface ofabase material.

[0037] The coating formation portion of an optical fiber is coated asfollows by using the mold constructed as described above. In this case,the coating formation portion of the optical fiber consists of twooptical fibers abutting and fusion-splice to each other (fusion-spliceportion).

[0038] (1) The upper mold 1 of the mold is opened and the optical fibersunited through fusion connection are arranged in the molding groove 6 ofthe lower mold 2. At this time, the coating formation portion ispositioned at the longitudinal center of the molding groove 6 or in thevicinity thereof.

[0039] (2) The upper mold 1 is put on the lower mold 2 to superimposethe joint surfaces 3 and 4 one upon the other. As a result, the moldinggrooves 5 and 6 are opposed to each other to define in a line thecylindrical molding portion 7 and the retaining portions 8; in themolding portion 7, the coating formation portion of the optical fiber isarranged, and, in the retaining portions 8, the coated portions of theoptical fibers on either side of the coating formation portion arearranged. The inner diameter of the molding portion 7 is somewhat largerthan the outer diameter of the coating formation portion of the opticalfiber, of which coating is peeled off, so that a space (molding space)is defined between the outer peripheral surface of the coating formationportion and the inner peripheral surface of the molding portion 7.

[0040] (3) A predetermined amount of UV curable resin is supplied to theinterior of the molding portion 7 through the supply passage 15 to fillthe molding space with UV curable resin.

[0041] (4) As shown in FIG. 2C, light is emitted from a light source 36previously arranged below the lower mold, and UV light is irradiated tothe mold from below. The UV light irradiated is transmitted through thelower mold 2 and is irradiated to the UV curable resin filling themolding space, whereby the UV curable resin cures, and firmly adheres tothe outer peripheral surface of the coating formation portion of theoptical fiber. In this case, the shading plates 20 a through 20 d areembedded in the lower mold 2, so that if some of the UV curable resinsupplied to the molding portion 7 extrudes to the exterior of moldingportion 7 (i.e., between the joint surfaces 3 and 4 of the upper andlower molds 1 and 2 superimposed one upon the other) or remains in thesupply passage 15, no UV light is irradiated to such UV curable resin tocause it to cure.

[0042] (5) When the UV curable resin has sufficiently cured, the uppermold 1 is opened, and the optical fiber is released.

[0043] By the above-described operations (1) through (5), the coatingformation portion of the optical fiber is coated. Here, the innerdiameter of the molding portion 7 is the same as or substantially thesame as the outer diameter of the optical fiber coated portions retainedin the retaining portions 8. Thus, the outer diameter of the coatingformation portion that has been coated is the same or substantially thesame as the outer diameter of the optical fiber coating.

[0044] (Embodiment Mode 2)

[0045] Another embodiment mode of the optical fiber coating formingdevice of the present invention will be described. As shown in FIG. 3,in this coating forming device, a mold 33 according to Embodiment Mode 1of the present invention is arranged on an upper surface 32 of a case 31to which a cover 30 is mounted so as to allow opening and closing. Thecover 30 and the case 31 are formed of a shading material, so that whenthe cover 30 is closed, the mold 33 is covered and shaded.

[0046] Contained in the case 31 are a container (tank) 34 containing UVcurable resin, a supplying device (pump) 35 for supplying the UV curableresin in the tank 34 to the molding portion 7 (FIG. 2A), a light source(UV light source) for generating UV light to be irradiated to the mold33, a high voltage power source 37 (FIG. 4) for supplying power to theUV light source 36, a photo sensor (UV sensor) 38 for detecting thequantity of UV light transmitted through the mold 33, and a control unit39 for controlling these components.

[0047] UV curable resin sent out from the pump 35 is supplied through asupply pipe (not shown) to the supply passage 15 (FIG. 2A) of the mold33, and is supplied from the supply passage 15 to the molding portion 7(FIG. 2A).

[0048] The control unit 39 controls the pump 35 and the UV light source36 as shown in FIG. 5 in accordance with a command output from anoperating panel 40 provided on the upper surface 32 of the case 31. Thecontrol is effected as follows:

[0049] (1) When a predetermined button of the operating panel 40 shownin FIG. 3 is operated, a command is output to the pump 35 to operate thepump 35, and, as shown in FIG. 5, the UV curable resin in the tank 34 issupplied to the interior of the molding portion 7 of the mold 33 where acoating formation portion 51 of an optical fiber 50 is arranged.

[0050] (2) When a predetermined amount of UV curable resin has beensupplied to the mold space of the molding portion 7, a predeterminedbutton on the operating panel 40 is operated to output a command to thepump 35 to stop the pump 35, and a command is output to the UV lightsource 36 to cause the UV light source 36 to emit light, irradiating UVlight to the mold 33 as shown in FIG. 2C. Here, as shown in FIGS. 2Athrough 2C, the shading plate 20 is embedded in the mold 33, so that theUV light irradiated to the mold 33 is thereby shaded, and no UV light isapplied to any UV curable resin extruding to the exterior of the moldingportion 7 (i.e., between the joint surfaces 3 and 4 of the upper andlower molds 1 and 2 superimposed one upon the other) or to the UVcurable resin remaining in the supply passage 15 (FIG. 2A) to cure suchUV curable resin.

[0051] (3) When a predetermined period of time has elapsed, apredetermined button on the operating panel 40 is operated to output acommand to the UV light source 36, causing the UV light source 36 tostop light emission.

[0052] The control unit 39 shown in FIG. 5 compares the quantity of UVlight detected by a photo sensor 38 (detected value) with a set value;when the detected value is less than the set value, a command is outputto a high-voltage power source 37 (FIG. 4) so as to increase the powersupply. Conversely, when the detected value is more than the set value,a command is output to the high-voltage power source 37 so as to reducethe power supply. Due to this control, the quantity of UV lightirradiated to the mold 33 is maintained at a fixed level.

[0053] As shown in FIG. 3, on either longitudinal side surface of thecase 31, there protrudes an L-shaped support 60, on which a clamp 61 isarranged. The clamps 61 nip and hold the coated portions of the opticalfiber 50 outwardly protruding from the longitudinal side surfaces of themold 33. The cover 30 has an observation window 62 which, when the coveris closed, makes it possible to observe the molding portion 7 (FIG. 2A)of the mold 33 and its periphery. Further, a shutter 63 (FIG. 3)slidable in the directions of the arrows of FIG. 4 is mounted to theobservation window 62. Thus, the observation window 62 is opened forobservation of the molding portion 7 and its periphery only whennecessary; otherwise, the window 62 is closed so that no external lightis irradiated to the molding portion 7 and its periphery.

[0054] (Embodiment Mode 3)

[0055] While in the mold shown in FIGS. 2A through 2C, the vertical hole13 is provided in the lower mold 2 to form the supply passage 15,through which UV curable resin can be supplied to the interior of themold, it is also possible, in the present invention, to cause thelateral grooves 10 and 11 respectively formed in the upper and lowermolds 1 and 2 of FIGS. 2A and 2B to open in the side surfaces of themolds 1 and 2; when the lateral groove 10 of the upper mold 1 and thelateral groove 11 of the lower mold 2 are opposed to each other, thereis formed a supply passage opening in the side surface of the mold, UVcurable resin being supplied into the mold through this supply passage.

[0056] The coating formation portion of the optical fiber that can becoated by the mold of the present invention and by the optical fibercoating forming device equipped therewith is not restricted to afusion-splice portion; for example, it may also be some other portion ofan optical fiber from which coating has been removed or an optical fibercore which is not coated.

[0057] In the optical fiber coating forming device of the presentinvention, it is also possible to provide a reflection portion whichreflects light transmitted through the mold and causes it to impingeupon the mold. In this case, it is desirable to provide a concavereflection surface in the reflection portion so that the received lightmay be condensed in the molding portion of the mold.

[0058] (Embodiment Mode 4)

[0059] Another embodiment mode of the optical fiber coating formingdevice of the present invention will be described with reference toFIGS. 6 through 11. In the coating forming device of FIG. 6, a case 140is formed by mounting a cover 74 to a device main body 73 so as to allowopening and closing; when the cover 74 is closed on the device main body73 as shown in FIG. 7, the case 140 forms a black box.

[0060] On either side surface of the device main body 73, there isprovided a support 141, upon which a clamp 72 for holding an opticalfiber 71 is provided. The clamp 72 is composed of a holder 142 and apresser cover 143 mounted thereto so as to allow opening and closing;after placing the optical fiber 71 on the holder 142 with the pressercover 143 open, the presser cover 143 is closed, whereby the opticalfiber 71 is clamped.

[0061] As shown in FIG. 6, the device main body 73 is equipped with amold 75 for shaping UV curable resin filling the outer periphery of theoptical fiber 71 into a desired configuration, a tank 110 for storing UVresin, a pump 79 for sending the UV curable resin in the tank 110 to asupply pipe 78, the supply pipe 78 for supplying UV curable resin to themold 75, a control unit 111 for controlling the control system, and anoperating panel 115. The device main body 73 is also equipped with a UVlight source 112 shown in FIG. 9, a UV sensor 114 for measuring thequantity of light from the UV light source 112, and a high-voltage powersource 116 (not shown)

[0062] As shown in FIGS. 6 and 7, an observation window 118 is providedin the cover 74, and a shutter 117 is provided in the observation windowso as to allow opening and closing. The shutter 117 may be of a desiredstructure, such as a door or a sliding door.

[0063] As shown in FIG. 1, in the mold 75, the upper mold 76 and thelower mold 77 are connected so as to allow opening and closing; at thecenter with respect to the longitudinal direction of the upper mold 76,there is formed a semi-cylindrical molding groove 120 that is downwardlyopen, and, at the center with respect to the longitudinal direction ofthe lower mold 77, there is formed a semi-cylindrical molding groove 121that is upwardly open. When the upper mold 76 is put on the lower mold77 to superimpose their joint surfaces one upon the other, the moldinggrooves 120 and 121 of the two molds are opposed to each other to definea cylindrical molding portion 113.

[0064] As shown in FIGS. 8A through 8C, a shading plate 129 is arrangedbehind the molding groove 120 of the upper mold 76, and this shadingplate 129 helps to prevent UV light from being applied to the UV curableresin extruding between the upper and lower molds 76 and 77. In front ofthe molding groove 120 and on top of a gate 125, there is arranged ashading plate 130 that is T-shaped in plan view, and this shading plate130 intercepts UV light so that no UV light may be applied to the UVcurable resin extruding between the upper and lower molds 76 and 77 andthe UV curable resin staying at the gate 125. Further, behind themolding groove 121 of the lower mold 77, there is arranged a shadingplate 126, which intercepts UV light so that no UV light may be appliedto the UV curable resin extruding between the upper and lower molds 76and 77. A shading plate 127 is arranged in front of the molding groove121 and the on the lower surface of the gate 125, and a shading plate128 is arranged on the outer side of the supply pipe 78; these shadingplates 127 and 128 intercept UV light so that no UV light may be appliedto the UV curable resin extruding between the upper and lower molds 76and 77 and the UV curable resin accumulated in the supply passage 122(the gate 125 and the supply pipe 78). These shading plates prevent UVlight from being applied to the UV curable resin, whereby curing of UVcurable resin in portions other than the molding grooves 120 and 121 isprevented.

[0065] The shading plates 126, 127, 128, 129, and 130 may consist, forexample, of metal plates, UV cutoff filters glued to substrates, coatingof UV cutoff resin, metal film formed on the mold 75 itself byevaporation, or UV cutoff resin coating formed on the mold.

[0066] As shown in FIG. 6, the mold 75 is accommodated in the devicemain body 73. The supply pipe 78 is connected to the molding groove 121of the mold 75 through the gate 125, the outlet of the supply pipe 78being arranged, and UV curable resin being supplied from the supply pipe78 to the molding groove 121 through the gate 125. As shown in FIG. 9, amirror 131 is arranged on the back surface of the mold 75, and a lampunit 135 is arranged on the front surface of the mold 75. The lamp unit135 contains a UV light source 112, and a mirror 132 is arranged behindit and to the left. The mirror 132 consists of a concave mirror. Aconcave mirror helps to enhance the condensing efficiency; on the otherhand, it involves an increase in thickness, which is disadvantageousfrom the viewpoint of reduction in size. By arranging the lamp unit 135and the mirror 132 at positions out of the field of view of the window118, it is possible to visually check the molding grooves 120 and 121 ofthe mold 75 through the window 118 of the cover 74.

[0067] The procedures for using the optical fiber coating forming deviceof FIGS. 6 and 7 are as follows. First, the cover 74, the upper mold 76,and the presser covers 143 are opened, and the optical fiber 71 isplaced on the holders 142 and in the molding groove 121 of the lowermold 77. Then, the upper mold 76 is closed to hold the optical fiber 71between the molding groove 120 of the upper mold 76 and the moldinggroove 121 of the lower mold 77. Further, the presser covers 143 areclosed so that the optical fiber 71 is held between the presser covers143 and the holders 142. Further, the cover 74 is closed to put thecasing 140 in a black-box state.

[0068]FIG. 10 shows the operation of the optical fiber coating formingdevice of FIG. 9. In FIG. 10, a portion of UV light emitted from the UVlight source 112 directly reaches the molding groove 121 to beirradiated to the UV curable resin filling the molding groove 121,curing this UV curable resin. At this time, the shading plates 126, 127,and 128 prevent UV light from being applied to the UV curable resinextruding between the upper and lower molds 76 and 77 and the UV curableresin accumulated in the supply passage 122 (the gate 125 and the supplypipe 78), whereby curing of the extruding UV curable resin and theaccumulated UV curable resin is prevented. The other portion of the UVlight emitted from the UV light source is reflected by the mirror 132,converged, and transmitted upwards. The UV light transmitted upwards isreflected by the mirror 131 and is directed toward the molding groove120 to be irradiated to the UV curable resin filling the molding groove120, thereby curing the UV curable resin. At this time, the shadingplates 129 and 130 prevent UV light from being applied to the UV curableresin extruding between the upper and lower molds 76 and 77 and to theUV curable resin accumulated in the gate 125, preventing curing of theUV curable resin. Further, it is possible to visually observe themolding grooves 120 and 121 through the window 118 of the cover 74 toconfirm the curing of the UV curable resin.

[0069]FIG. 11 shows the operation of the control system of the opticalfiber coating forming device. The control unit 111 operates thesupplying device (pump) 79 in accordance with a command from theoperating panel 115 to send the UV curable resin in the tank 110 intothe mold 75 through the supply pipe 78. The light emission amount forthe UV light source 112 is set on the operating panel 115; when acommand for light emission is issued, the UV light source 112 is lit upby high voltage supplied from the high-voltage power source 116 throughthe control unit 111. The light emitting condition of the UV lightsource 112 is detected (observed) by a UV sensor 114 and sent to thecontrol unit 111. The control unit 111 compares the set value determinedat the operating panel 115 with the detected value from the UV sensor114 to automatically effect correction to a predetermined value.

[0070] (Embodiment Mode 5)

[0071]FIG. 12 shows another embodiment mode of the optical fiber coatingforming device of the present invention. In FIG. 12, the mold 75 and thelamp unit 135 are accommodated in the device main body 73. A lens 134 isformed on the lower mold 77 constituting a part of the mold 75. The lampunit 135 is equipped with the UV light source 112 and the mirror 133arranged behind it. The lamp unit 135 is arranged below the lens 134.

[0072] The cover 74 shown in FIG. 12 has an observation window 118 forobserving the molding grooves 120 and 121 of the mold 75; the window isequipped with a shutter (sliding door) 117 that can be opened andclosed. A mirror 136 is mounted to the shutter 117; when the shutter 117is opened, the mirror 136 moves over the back surface of the mold 75 tobe placed in the position indicated by the imaginary line in FIG. 12,thereby securing the field of view from the window 118. The lens 134 ofFIG. 12 may also be separate from the lower mold 77.

[0073] (Embodiment Mode 6)

[0074]FIG. 13 shows an example of the operation of the optical fibercoating forming device of FIG. 12. A portion of the UV light emittedfrom the UV light source 112 travels directly upwards, and anotherportion thereof is reflected by the mirror 133 of the lamp unit 135 andthen transmitted upwards. The UV light transmitted upwards is convergedby the lens 134 formed on the lower mold 77. A portion of the convergedUV light travels directly toward the molding groove 121 and isirradiated to the UV curable resin filling the molding groove 121,thereby curing the UV curable resin. At this time, the shading plates126, 127, and 128 prevent UV light from being applied to the UV curableresin extruding between the upper and lower molds 76 and 77 and to theUV curable resin accumulated in the supply passage 122 (the gate 125 andthe supply pipe 78), thereby preventing curing of the UV curable resin.Another portion of the UV light converged by the lens 134 is reflectedby the mirror 136 and travels toward the molding groove 120 and isirradiated to the UV curable resin filling the molding groove 120,thereby curing the UV curable resin. At this time, the shading plates129 and 130 prevent UV light from being applied to the UV curable resinextruding between the upper and lower molds 76 and 77, therebypreventing curing of the UV curable resin.

INDUSTRIAL APPLICABILITY

[0075] The optical fiber coating mold as claimed in claim 1 of thepresent application, in which shading plates are arranged around themolding portion to be filled with UV curable resin, provides thefollowing effect.

[0076] Even if some of the UV curable resin filling the molding portionextrudes from the molding portion, no light is irradiated to theextruding UV curable resin. Thus, the separation of the upper and lowermolds is not hindered by cured UV curable resin, nor does cured resinadhere to the coated portion to generate burr.

[0077] The optical fiber coating mold as claimed in claim 2 of thepresent application, in which a shading plate is arranged on the outerside of the supply passage for supplying UV curable resin to the moldingportion, provides the following effect.

[0078] Even if some UV curable resin remains in the supply passage, nolight is applied to the remaining UV curable resin. Thus, the supplypassage is not clogged by cured UV curable resin.

[0079] The optical fiber coating forming device as claimed in claim 3 ofthe present application, which is comprised of a mold providing theabove-described effects, provides the same effects as described above.Further, provided in a case are a container for containing UV curableresin, a supplying device for supplying the UV curable resin in thecontainer to the molding portion of the mold, a light source foremitting light to be irradiated to the mold, and a control unit forcontrolling the supplying device and the light source, so that it ispossible to automatically perform with a single optical fiber coatingforming device the supply of UV curable resin to the molding portion andcontrol thereof as well as the irradiation of UV light to the UV curableresin and control thereof.

[0080] The optical fiber coating forming device as claimed in claims 4through-8 provides the following effects.

[0081] 1. Due to the provision of a mirror or a lens for reflecting UVlight to UV curable resin, it is possible to efficiently utilize UVlight by transmitting UV light converged by the mirror or the lens tothe molding groove of the mold, making it possible to cure the UWcurable resin efficiently and reliably in a short time.

[0082] 2. Due to the efficient utilization of UV light, it is possibleto achieve power saving, and it is possible to achieve a reduction inthe size and weight of the UV lamp lighting system, in particular, thehigh-voltage power source.

[0083] 3. Due to the arrangement of the mirror or the lens at positionswhere the field of view for the observation window is secured, it iseasier to check the way the optical fiber is set, the way the mold isfilled with UV curable resin, etc.

[0084] 4. In the optical fiber coating forming device as claimed inclaim 5, the reflection plate provided behind the mold is flat, so thatthe incorporation of the reflection plate into the main body isfacilitated and, further, it is possible to achieve a reduction in thesize and thickness of the optical fiber coating forming device, therebyachieving an improvement in assembly operability.

[0085] 5. In the optical fiber coating forming device as claimed inclaim 6, the mirror or the lens is arranged on the back surface or theside surface, so that the field of view for the observation window forobserving the interior is secured, making it possible to coat thecoating formation portion of an optical fiber while observing theinterior.

[0086] 6. In the optical fiber coating forming device as claimed inclaim 7, both or one of the mirror and the lens is movable, so that whenirradiating UV light to UV curable resin, the mirror or the lens ismoved to a position where it does not interfere with UV lightirradiation; when observing the interior, the mirror or the lens ismoved to a position where it does not interfere with the observation, sothat it is possible to efficiently apply UV light and to easily observethe interior.

[0087] 7. In the optical fiber coating forming device as claimed inclaim 8, a shading plate for preventing irradiation of UV light to UVcurable resin in places other than the molding groove (places where noirradiation of UV light is needed) is provided in the vicinity of themolding groove of the mold, so that it is possible to prevent curing ofUV curable resin in places where no irradiation of UV light is needed.

1. An optical fiber coating mold which is comprised of upper and lowermolds having joint surfaces, molding grooves being formed in the jointsurfaces of the upper and lower molds, a molding portion where a coatingformation portion of an optical fiber can be arranged and a supplypassage for supplying UV curable resin being formed between the opposingmolding grooves of the upper and lower molds when the joint surfaces ofthe upper and lower molds are superimposed one upon the other, themolding portion being filled with UV curable resin through the supplypassage after arranging the coating formation portion of the opticalfiber in the molding portion, the coating formation portion of theoptical fiber being coated with the UV curable resin when the UV curableresin is cured by irradiating light thereto from outside, characterizedin that a shading plate is arranged in the periphery of the moldingportion.
 2. An optical fiber coating mold according to claim 1,characterized in that a shading plate for preventing light irradiatedfrom outside from entering the supply passage is arranged on the outerside of the supply passage.
 3. An optical fiber coating forming devicein which a coating formation portion of an optical fiber is set in amolding portion of a mold set in a case, the outer periphery of thecoating formation portion of the optical fiber in the molding portionbeing filled with UV curable resin, the outer periphery of the coatingformation portion of the optical fiber being coated with the UV curableresin when the resin is cured by irradiating UV light thereto,characterized in that said mold consists of a mold as set forth in claim1 or 2, and said case contains a container for containing UV curableresin, a supplying device for supplying the UV curable resin in thecontainer to the interior of the molding portion of the mold, a lightsource for generating UV light to be irradiated to the mold, and acontrol unit for controlling the supplying device and the light source.4. An optical fiber coating forming device in which a coating formationportion of an optical fiber is set in a molding portion of a mold set ina case, the outer periphery of the coating formation portion in themolding portion being filled with UV curable resin, the outer peripheryof the coating formation portion of the optical fiber being coated withthe UV curable resin when the resin is cured by irradiating UV lightthereto, characterized in that a mirror or a lens for reflecting UVlight to UV curable resin is provided in the case, the mirror or thelens being provided so as to secure the field of view for an observationwindow for the interior of the case.
 5. An optical fiber coating formingdevice according to claim 4, characterized in that a flat reflectionplate is provided behind the mold.
 6. An optical fiber coating formingdevice according to claim 4, characterized in that a mirror or a lens isarranged behind or at a side of the light source.
 7. An optical fibercoating forming device according to one of claims 4 through 6,characterized in that both or one of the mirror and the lens is movable.8. An optical fiber coating forming device according to one of claims 4through 6, characterized in that a shading plate for preventingirradiation of UV light to UV curable resin in a place other than themolding portion is provided in the vicinity of the molding portion ofthe mold.
 9. An optical fiber coating forming device according to claim7, characterized in that a shading plate for preventing irradiation ofUV light to UV curable resin in a plate other than the molding portionis provided in the vicinity of the molding portion of the mold.